• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.140-140
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• 2010

Non-mass analyzed ion shower doping (ISD) technique with a bucket-type ion source or mass-analyzed ion implantation with a ribbon beam-type has been used for source/drain doping, for LDD (lightly-doped-drain) formation, and for channel doping in fabrication of low-temperature poly-Si thin-film transistors (LTPS-TFT's). We reported an abnormal activation behavior in boron doped poly-Si where reverse annealing, the loss of electrically active boron concentration, was found in the temperature ranges between $400^{\circ}C$ and $650^{\circ}C$ using isochronal furnace annealing. We also reported reverse annealing behavior of sequential lateral solidification (SLS) poly-Si using isothermal rapid thermal annealing (RTA). We report here the importance of implantation conditions on the dopant activation. Through-doping conditions with higher energies and doses were intentionally chosen to understand reverse annealing behavior. We observed that the implantation condition plays a critical role on dopant activation. We found a certain implantation condition with which the sheet resistance is not changed at all upon activation annealing.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.350-354
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• 2018

Lifetime study of blue phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes was carried out to understand the dominant degradation process during electrical operation of the devices. Doping concentration dependence of the phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes was studied, which demonstrated long lifetime at low doping concentration in the phosphorescent devices and at high doping concentration in the thermally activated delayed fluorescent devices. Detailed mechanism study of the two devices described that triplet-triplet annihilation is the main degradation process of phosphorescent organic light-emitting diodes, whereas triplet-polaron annihilation is the key degradation factor of the thermally activated delayed fluorescent devices.

• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.241-244
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• 2012

Antimony doped tin oxide (ATO) thin films on glass substrate were prepared by the chemical solution deposition (CSD) method, using sol-gel solution synthesized by non-alkoxide precursors and the sol-gel route. The crystallinity and electrical properties of ATO thin films were investigated as a function of the annealing condition (both annealing environments and temperatures), and antimony (Sb) doping concentration. Electrical resistivity, carrier concentration, Hall mobility and optical transmittance of ATO thin films were improved by Sb doping up to 5~8 mol% and annealing in a low vacuum atmosphere, compared to the undoped tin oxide counterpart. 5 mol% Sb doped ATO film annealed at $550^{\circ}C$ in a low vacuum atmosphere showed the highest electrical properties, with electrical resistivity of about $8{\sim}10{\times}10^{-3}{\Omega}{\cdot}cm$, and optical transmittance of ~85% in the visible range. Our research demonstrates the feasibility of low-cost solution-processed transparent conductive oxide thin films, by controlling the appropriate doping concentration and annealing conditions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.369.2-369.2
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• 2014

Diamond-like Carbon(DLC) films doping Si were deposited by linear ion source(LIS)-physical vapor deposition method on Si wafer. We have studied the effects of Si content on friction and wear properties of DLC films and the characteristics of the films were investigated using Nano-indentation, Micro raman spectroscopy, Field Emission-Scanning Electron Microscope (FM-SEM) and X-ray Photoelectron Spectroscopy (XPS). The films has been various low-friction and low-stress by varying the flow rates of silane gas. Under the about 2% of Si doping is very suitable for improving the adhesion of films and reducing internal stress while maintaining the surfaces hardness of DLC films. Linear ion source (LIS)를 사용하여 Si wafer위에 Si 이온이 첨가된 DLC 박막을 증착하였다. 참가된Si 이온의 양에 따라 DLC 박막에 미치는 영향을 분석하기 위하여 마찰 계수 및 경도를 비교하였고, Micro raman spectroscopy, Field Emission-Scanning Electron Microscope (FM-SEM) and X-ray Photoelectron Spectroscopy (XPS)를 통하여 표면 상태를 분석하였다. 천체 주입된 가스량의 약 2%까지 Si 이온 주입이 늘어날수록 DLC 박막의 마찰계수는 낮아졌고, 경도는 Si 이온이 주입되지 않았을 경우와 비슷한 값(약 20~23 GPa)을 가졌다. 2% 이상의 주입량에서는 마찰계수는 주입량이 늘어날수록 높아졌으며 경도는 떨어지는 경향을 보였다. 이는 Si이온이 2%이하로 첨가되었을 경우, DLC 박막의 생성시 탄소 이온들의 결합 Stress를 줄여 마찰계수가 줄어든다고 볼 수 있으며, 그 양이 2%이상이 되면 오히려 불순물로 작용하여 DLC 박막의 Stress는 급격히 증가하고 마찰계수도 높아짐을 알 수 있다.

• 한국정보통신학회논문지
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• 제18권9호
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• pp.2183-2188
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• 2014

본 연구에서는 비대칭 이중게이트(double gate; DG) MOSFET의 채널 도핑농도 변화에 따른 문턱전압이동 현상에 대하여 분석하였다. 비대칭 DGMOSFET는 일반적으로 저 농도로 채널을 도핑하여 완전결핍상태로 동작하도록 제작한다. 불순물산란의 감소에 의한 고속 동작이 가능하므로 고주파소자에 응용할 수 있다는 장점이 있다. 미세소자에서 필연적으로 발생하고 있는 단채널 효과 중 문턱전압이동현상이 비대칭 DGMOSFET의 채널도핑농도의 변화에 따라 관찰하고자 한다. 문턱전압을 구하기 위하여 해석학적 전위분포를 포아송방정식으로부터 급수형태로 유도하였다. 채널길이와 두께, 산화막 두께 및 도핑분포함수의 변화 등을 파라미터로 하여 도핑농도에 따라 문턱전압의 이동현상을 관찰하였다. 결과적으로 도핑농도가 증가하면 문턱전압이 증가하였으며 채널길이가 감소하면 문턱전압이 크게 감소하였다. 또한 채널두께와 하단게이트 전압이 감소하면 문턱전압이 크게 증가하는 것을 알 수 있었다. 마지막으로 산화막 두께가 감소하면 문턱전압이 증가하는 것을 알 수 있었다.

• 한국재료학회지
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• 제19권11호
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• pp.607-612
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• 2009

We investigated the effects of Co doping on the NO gas sensing characteristics of ZnO-carbon nanotube (ZnO-CNT) layered composites fabricated by coaxial coating of single-walled CNTs with ZnO using pulsed laser deposition. Structural examinations clearly confirmed a distinct nanostructure of the CNTs coated with ZnO nanoparticles of an average diameter as small as 10 nm and showed little influence of doping 1 at.% Co into ZnO on the morphology of the ZnO-CNT composites. It was found from the gas sensing measurements that 1 at.% Co doping into ZnO gave rise to a significant improvement in the response of the ZnO-CNT composite sensor to NO gas exposure. In particular, the Co-doped ZnO-CNT composite sensor shows a highly sensitive and fast response to NO gas at relatively low temperatures and even at low NO concentrations. The observed significant improvement of the NO gas sensing properties is attributed to an increase in the specific surface area and the role as a catalyst of the doped Co elements. These results suggest that Co-doped ZnOCNT composites are suitable for use as practical high-performance NO gas sensors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.244-244
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• 2010

Doping process of crystalline silicon solar cell process is very important which is as influential on efficiency of solar. Doping process consists of pre -deposition and diffusion. Each of these processes is important in the process temperature and process time. Through these process conditions variable, p-n junction depth can be controled to low and high. In this paper, we studied a optimized doping pre-deposition temperature for high solar cell efficiency. Using a $200{\mu}m$ thickness multi-crystalline silicon wafer, fixed conditions are texture condition, sheet resistance($50\;{\Omega}/sq$), ARC thickness(80nm), metal formation condition and edge isolation condition. The three variable conditions of pre-deposition temperature are $790^{\circ}C$, $805^{\circ}C$ and $820^{\circ}C$. In the $790^{\circ}C$ pre-deposition temperature, we achieved a best solar cell efficiency of 16.2%. Through this experiment result, we find a high efficiency condition in a low pre-deposition temperature than the high pre-deposition temperature. We optimized a pre-deposition temperature for high solar cell efficiency.

• 한국전기전자재료학회논문지
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• 제30권6호
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• pp.345-348
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• 2017

In this work, static characteristics of 4H-SiC SJ-ACCUFETs were obtained by adjusting the p-pillar region. The structure of this SJ-ACCUFET was designed by using a two-dimensional simulator. The static characteristics of SJ-ACCUFET, such as the breakdown voltages, on-resistance, and figure of merits, were obtained by varying the p-pillar doping concentration from $1{\times}10^{15}cm^{-3}$ to $5{\times}10^{16}cm^{-3}$ and the thickness from $0{\mu}m$ to $9{\mu}m$. The doping concentration and the thickness of p-pillar region are closely related to the break down voltage and on-resistance and threshold voltages. Hence a silicon carbide SJ-ACCUFET structure with highly intensified breakdown voltages and low on-resistances with good figure of merits can be achieved by optimizing the p-pillar thickness and doping concentration.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.249-254
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• 2008

Ag doping effect on $Li[Ni_{0.2}Li_{0.2}Mn_{0.6}]O_2$ cathode material was studied. Specially, we focused on rate performance of Ag doped samples. The $Li[Ni_{0.2}Li_{0.2}Mn_{0.6}]O_2$ powder was prepared by simple combustion method and the Ag was doped using $AgNO_3$ during gelation process. Based on X-ray diffraction analysis, there was no structural change by Ag doping, but the 'metallic' form of Ag was included in the doped powder. Both bare and Ag 1 wt.% doped sample showed similar discharge capacity of 242 mAh/g at 0.2C rate. However, as the increase of charge-discharge rate to 3C, Ag 1 wt.% doped sample showed higher discharge capacity (172 mAh/g) and better cyclic performance than those of bare sample. The discharge capacity of Ag 5 wt.% doped sample was relatively low at all rate condition. However it displayed better rate performance than other samples.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.314-316
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• 1997

We have studied the epitaxial growth and electrical properties of $Si_{0.8}Ge_{0.2}$, films on Si substrates at $550^{\circ}C$ by LPCVD. In a low $PH_3$, partial pressure region such as below 1.25 mPa, the phosphorus doping concentration increased proportionally with increasing $PH_3$ partial pressure while the deposition rate and the Ge fraction x were constant. In a higher $PH_3$ partial pressure region, the phosphorus doping concentration and the deposition rate decreased, while the Ge fraction slightly increased. The dependence of P incorporation rate on the $PH_3$ partial pressure was similar to the phosphorus doping concentration. According to test results, it suggests that high surface coverage of phosphorus atoms suppress both the $SiH_4$ adsorption/reaction and the $GeH_4$ adsorption/reaction on the surfaces, and the effect is more stronger on $SiH_4$ than on $GeH_4$. In a higher $PH_3$ partial pressure region, the deposition is largely controlled by surface coverage effect of phosphorus atoms.